DESIGN AND APPLICATION OF A FEMTOSECOND OPTICAL PARAMETRIC OSCILLATOR FOR TIME-RESOLVED SPECTROSCOPY OF SEMICONDUCTOR HETEROSTRUCTURES

Femtosecond pulses of a collinearly pumped Optical Parametric Oscillator (OPO) are applied for investigations of the carrier dynamics in ternary and quaternary semiconductor quantum wells. The design and the specifications of the OPO are given in detail. We show that no measurable jitter exists between the pump pulses and the output pulses of the OPO. Therefore, it is possible to use the OPO and its pump laser for two-color experiments with a time resolution limited by the pulse lengths. We present and discuss results of transient four-wave mixing experiments on (InGa) As/InP quantum wells, and find a new kind of polarization-dependent quantum beat phenomenon. In addition, non-degenerate experiments on quantum wells from the quaternary (InGaAl) As material system, using two pulses at different wavelengths (one from the OPO and one from the pump laser), are discussed as a novel experimental technique to study carrier trapping into quantum wells.